Re: [PATCH 1/2] mmc: dw_mmc: retry to switch voltage when failed

[Jaehoon Chung <jh80.chung@samsung.com>]

Hi Shawn,

On 05/04/2016 07:41 PM, Shawn Lin wrote:
> 在 2016/5/4 15:14, Jaehoon Chung 写道:
>> If vqmmc is used and failed to switch voltage, then retry to switch
>> voltage. MMC core is providing the retrying scheame.
>>
>> Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
>> ---
>>  drivers/mmc/host/dw_mmc.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> index 9dd1bd3..28602cc 100644
>> --- a/drivers/mmc/host/dw_mmc.c
>> +++ b/drivers/mmc/host/dw_mmc.c
>> @@ -1416,7 +1416,7 @@ static int dw_mci_switch_voltage(struct mmc_host *mmc, struct mmc_ios *ios)
>>              dev_dbg(&mmc->class_dev,
>>                       "Regulator set error %d - %s V\n",
>>                       ret, uhs & v18 ? "1.8" : "3.3");
>> -            return ret;
>> +            return -EAGAIN;
>>          }
>>      }
> 
> If not vqmmc is assigned, dw_mci_switch_voltage still returns success to
> mmc core?

There is comment in dw_mci_switch_voltage().. In some SoC, it's not harmful to switch voltage.
But we can decide this condition whether try to set both or not. 

Best Regards,
Jaehoon Chung

> 
>>      mci_writel(host, UHS_REG, uhs);
>>
> 
>